Boom loader for overhead crane



Aug. 5, 1958 R. T. MOORE BOOM LOADER FOR OVERHEAD CRANE 4 Sheets-Sheet 1Filed Feb. v. 1955 Aug. 5, 1958 R. T. MOORE BOOM LOADER FOR OVERHEADCRANE 4 Sheets-Sheet Z.

Filed Feb. 7, 1955 R. T. MOORE BOOM LOADER FOR OVERHEAD CRANE Aug. s,195s 4 Sheets-Sheet 3 Filed Feb. 7, 1955 IN VEN TOR.

Aug. 5, i958 R. T. MOORE BOOM LOADER FOR OVERHEAD CRANE 4 sheets-sheet 4Filed Feb. 7, 1955 ,Nm/ D. E D D my @mm1 /INVENTOR W/ Wma,

United tates EGSM LADER FR VERHEAD CRANE Application February 7, 1955,Serial No. 455,551

4 Claims. (Cl. 212-17) This invention relates to material-handlingequipment -n1ore particularly, to overhead cranes of the type thattravel along tracks for servicing a work or storage area.

One of the limitations of an overhead crane is the restriction of itseffective load-handling to the area over which a truck or carriage ismovable, it being necessary to locate the truck or carriage verticallyabove the load, in order that the hook or sling of the hoist or otherlifting mechanism carried by the truck or carriage can be loweredvertically to the load and act on the latter without horizontal forcecomponents. The present invention is concerned with extending theeffective work area coverage of an overhead traveling crane and withproviding such a crane with a different type of load handling facility,it being the principle object of the invention to provide a low headroomcrane capable of applying a vertical lifting force to a load locatedoutside or beyond the vertical projection of the crane carriage.

Another object is to provide a crane which is capable of shifting therelative position of the load and the carriage or carrier of the crane,so that, in use, a number of loads can be serviced Without moving thecarrier or, if desired, the crane can be oriented in various positionsrelative to a single load, so as to facilitate the handling of suchload.

ln its broader aspects, the invention contemplates a crane having a boommounted on a carrier or truck as by being suspended below such carrier.The boom is pivotally attached to the crane carrier, the pivotalconnection constraining the boo-m to relative swing movements in avertical plane. An actuator is connected between a point on the carrierand a point on the beam,

each spaced from the point of pivotal connection, so as to impart leveraction to the boom. In the contemplated arrangement, one end of the boomis pivoted on the carrier and the other, or load-carrying, end of theboom extends beyond the vertical projection of the carrier. In sucharrangement, the actuator conveniently takes the form of a hoistconnected between a point on the carrier spaced from the pivotalconnection of the boom and a point on the boom intermediate the pivotand loadcarrying ends, constituting the boom a third `degree lever. As aspecialized version of the invention, a latch mechanism comprising anelement on the carrier and an element on the boom is provided for thepurpose of fastening the boom in predetermined relation to the carrier,the boom preferably being in raised position when so latched, so as torelieve the hoist actuator of load with attendant safety and operatingadvantages. As a still further refinement of this aspect of theinvention, a detachable connection is provided between the hoist and theboom so that with the boom latched in raised position, the hoist isavailable for vconventional direct-lift load-handling operations.

As a further variation of the crane-boom arrangement referred to, and asanother objective of the invention, the boom is mounted on the cranecarrier for relative rotative or swiveling movement about a verticalaxis, this being a preferred way of accomplishing the orientation of thecarrier and the load-lifting end of the boom in different relativepositions. In providing for rotative movement of the boom relative tothe carrier, the wheels and rails of the crane structure are relieved ofhorizontal force components resulting from moments caused by theeccentric loading of the crane resulting from the application of a loadto the horizontally projecting boom. In the preferred arrangement,horizontal force components are carried by a specialized component ofthe carrier herein called a stiifener or strut member that is disposedin the vertical swing plane of the boom and is coupled to the boom toturn with the latter, this being one of the more specialized objectivesof the invention.

In the operation of an overhead traveling crane equipped with alever-type boom of the character referred to, one of the limitingfactors governing the weight of the load that can be handledsatisfactorily is the tendency of the crane, truck or carrier to betilted on the tracks by reason of the application of a vertical load tothe outer end of the boom. The structural arrangement of the presentinvention lends itself to convenient location of counter-balancingweights or loads on the carrier,

strut or boom for the purpose of increasing the capacity of the boomwith respect to loads applied to the boom outer end. In certainapplications of the invention, it is feasible to mount heavy components,such as drive motors, on the inner, or base, Aend of the boom or on thestrut or other part of the carrier adjacent the pivot, utilizing suchcomponents as counter-weights in augmenting the effective load-carryingcapacity of the boom. A hoist for raising and lowering the boom may, forexample, constitute one such counter-balancing weight. Anothercounter-balancing Weight may be the electric drive for a mechanical grabor the like, the grab structure being on the outer or load-carrying endof the boom and the drive therefore being at or beyond the pivot end ofthe boom to constitute a counter-weight.

Other objects and advantages pertain to certain novel features ofconstruction and combinations and arrangements of parts which provide acompact, relatively inexpensive crane-boom combination, simple inconstruction and design, inexpensive to manufacture, erect and servicein the field, as will become apparent from the following detaileddescription of the invention made in connection with the accompanyingdrawings, forming a part of the specification.

In the drawings:

Fig. l is a fragmentary, partly diagrammatic, side elevational view,partly in section and with parts broken away and removed, of a suspendedoverhead crane incorporating a boom-carrier combination and embodyingthe principles of the present invention, this view showing in phantomthe application of the device to the placement of cargo inside thecovered body of a truck or van;

Fig. 2 is a plan view, partly diagrammatic, partly in section and withparts broken away and removed, of the crane structure of Fig. l;

Fig. 3 is a fragmentary sectional detail through the boom pivot member,this view being taken substantially in the plane indicated at 3-3 ofFig. l and enlarged with respect to that figure;

Fig. 4 is a fragmentary elevational detail, partly in section and withparts broken away and removed, showing the boom trolley, this view beingtaken substantially in the plane indicated at 4 4 of Fig. 2 and enlargedwith respect to that figure;

Fig. 5 is a fragmentary elevational detail, partly in section and withparts broken away and removed, showing the trolley wheel suspension bywhich the carrier is mounted on the traveling bridge;

Fig. 6 is a fragmentary side elevational view, partly in section andwith parts broken away and removed,

showing a modification of the invention, incorporating 360 rotativemovement of the boom on and relative to the carrier, this view beingotherwise similar to Fig. 1.

Fig. 7 is a fragmentary sectional detail through the boom to show theseparable connection between the hoist and the boom, this view beingtaken substantially in the plane indicated at 7 7 of Fig. 6 and enlargedwith respect to that figure;

Fig. 8 is a fragmentary elevational View, partly in section and withparts broken away and removed, showing the latch structure forinterconnecting the boom and the carrier strut;

Fig. 9 is a fragmentary plan view, partly in section and with partsbroken away and removed, of the boomcrane combination of Fig. 6;

Fig. l0 is a fragmentary elevational detail, partly in section and withparts removed, showing one of the strut suspending trolleys of theembodiment of Figs. 6 and 9,

this view being taken substantially in the plane indicated at 10-10 ofFig. 6 and enlarged with respect to that figure; and

Fig. ll is a fragmentary elevational detail, partly in section and withparts broken away and removed, showing the vertical pivot guiding therotation of the boom structure in the embodiment of Figs. 6 and 9, thisview being taken substantially in the plane 11--11 of Fig. 9 andenlarged with respect to that gure.

Traveling cranes, particularly cranes of the low headroom type, aredesigned for suspension from one or more horizontal rails or tracks thatare suitably secured to the structure of the building in which the craneis installed or on suitable stanchions or uprights erected for thepurpose. The crane rails may consist of short, straight runs or they`may comprise a vertical network, interconnecti ing and interlocking insuch a way as to permit a crane bearing a load to travel from one pointto any of a number of destinations within a plant, shop or yard servicedby the crane system. In many instances, however, it is not feasible toconstruct overhead rails that `will enable a crane to move into everypart of the establishment in which it is installed and, of course, it isvirtually impossible to extend the rails of an overhead crane systeminto the interior of -a box car, truck or van to be loaded.

The boom-crane combination of the present invention is provided toextend the load lifting ability of the overhead crane beyond thevertical projection of the crane bridge and carrier so as to cover areaswhich are beyond or outside the reach of the crane rails. While theinvention is applicable to overhead cranes of the type that travel ".i

on single tracks, it is most practical and useful in connection withtraveling overhead cranes of the double bridge type that are mounted onspaced parallel tracks, the boom being suspended from a carrier thattravels back and forth on the bridge transversely to the direction oftravel of the bridge structure along the rails, such a structuralarrangement representing the best known mode of practicing theinvention.

Referring now to the drawings,y one of the rolled steel I-section runwayrails for supporting the double bridge crane is indicated at 1, it beingunderstood that a similar rail 1s provided at the other end of bridge A,both rails belng suitably secured to the building or other supportlngstructure so that the rails are parallel to one another, all inaccordance with conventional practice in erecting overhead crane rails.At the opposite ends of the bridge A and arranged to travel along therails are trucks. Only one truck is `shown in the drawings, the otherbeing the same, comprising a pair of spaced parallel steel channel framemembers 2 that are located one on each side of the vertical plane of therail with which it is associated. These frame members extend between andconnect the ends of the main bridge capsor channel memb ers 7, to whichthey are rigidly secured as by bolting, riveting or welding. The bridgestructure thus comprises a rectangular frame which is suspended from therunway rails by trolley wheels 3. These trolley wheels may comprisesingle pairs, as shown at the left in Figs. l and 2, or double pairs, asshown at the right in these figures. The trolley wheel pairs are eachcarried by stub shafts fast in a yoke 4. In the case of the single pairof trolley wheels (at the left in Figs. l and 2) the yoke receives arigid element projecting from the bridge frame and thus carries the loaddirectly. In the case of the double pair of trolleys (at the right inFigs. l and 2) the yokes 4 are connected as by a load bar 5 whichreceives a transverse element 46 (Fig. 2) secured between theoverhanging ends of the truck frame members 2. ln the arrangement shownthe double pairs of trolleys are employed at the right-hand side of thebridge frame to carry the relatively greater load imposed on such sideof the 'bridge by reason of the eccentric loading resulting from theboom Structure, as will appear. Thus the overhanging or projectingarrangement of the tinck members 2 with respect to one of the mainbridge members 7 obtains certain advantages such as increased stabilityand load carrying capacity. It is apparent that it is feasible to usesingle trolley pairs at each side of the truck or, if desired, thedou-ble pairs of trolleys may be used at both sides, as will appear.Movement of the crane bridge to and fro along the runway rails 1 isaccomplished conventionally as by rubber-tired drive wheels one of whichis indicated at 30 actuated by a drive shaft 31 and a suitable motor(not shown). The drive wheels frictionally engage the underside of thebottom fianges of the runway rail-s 1 and the drive motor is energizedthrough conventional controls.

Suspended beneath the traveling double bridge for movement along thelatter transversely to the direction of movement of the bridge along therail or rails 1 is a carrier C that also is of rectangular frameconstruction and has trolley wheels 6 in pairs that ride along thebottom anges of I-beam rails 8 secured to the underside of the mainbridge cap members 7. In the arrangement illustrated the bridge members7 may comprise rolled steel channels disposed and spaced in parallelrelation with their channels opening downwardly. The carrier rails 8 arethen disposed with their upper flanges against the web portions of thechannel members 7 and secured by the usual welding, riveting or bolting.

The carrier frame comprises pairs of spaced parallel truck members 10,one pair associated with each of the carrier rails 8, and spacedparallel transverse members 1l which extend across and are rigidlyconnected to the ends of all of the truck members. The wheels 6 arecarried on stub shafts as are the bridge wheels 3, the stub shafts ofthe carrier wheels being held in yokes 9 that receive the stems of loadcarrying elements 37 (Fig. 5) disposed Abetween the carrier framemembers 10 and 11 and held in place as by ybolts 38 which extend throughthe members and elements. The load carrying elements 37 are eachT-shaped in plan form, the head of the T being clamped between or heldfast to the frame members of the carrier, and the stem of the Textending into the -saddle of the yoke and resting on a locating andcentering element 39 supported as by a suitable anti-friction bearing.

While the cross-sectional shapes of the various bridge frame and carrierframe members may vary, these parts are made of conventional rolledsteel sections suitably selected as to size and shape to carry the loadsfor which the particular crane system is designed, all in accordancewith customary crane design practice.

Mounted on the carrier C, preferably in suspended relation below thebridge structure and also below the carrier, is a boom B which isarranged so that its forward or load carrying end (at the right in Figs.l and 2) extends laterally beyond the vertical projection of the carrierand thereby increases the area over which the load carryying ability ofthe crane is effective. The suspension of the boom incorporates arotative swivel arrangement which permits side to side swaying of theboom in addition to its up and down or lcad lifting movement. The up anddownswinging of the boom and also the swiveling or rotating of the boomrelative to the carrier are accommodated in pivots associated with block17 disposed at the inner or base end of the boom. This block, comprisinga steel forging or machining capable of withstanding strong shearing,twisting and bending forces, includes an integral vertical or upstandingpin portion 40 which is received through a central opening in lower ange41 of a supporting or I-beam 14 secured to short supplemental framemembers 36 that are connected in spaced parallel relation to one anotherbetween one of the pairs of carrier truck members (Fig. 2). The web ofthe pivot beam 14 is suitably reinforced as by gusset plates 42 and isformed with a cutout 43 adjacent the lower ange 41, this cutoutaccommodating the pivot pin 40 and a nut 15 screwed onto the threadedupper end of the pivot pin. A thrust assembly 16 is interposed `betweenthe nut and the flange of the beam. A transverse pin through the nut andthe pivot pin 40 prevents turning of the nut on the pin.

The pivot block 17 constitutes a support or anchorage on the carrier Cfor the left-hand end (as viewed in Fig. 1) of both a strut assembly Sand the boom B. The strut assembly comprises a pair of rolled steelchannels 19 disposed in parallel relation to one another with their openchannels facing. At their ends the anges of the strut channels areremoved, leaving web portions which at 'the pivot end of the strut areindicated at 49 and are received on opposite sides of the pivot block17. Against the outside surfaces of the struts are received hinge plates18, these hinge plates being located one on each side of the pivotblock. A pin 27 is received through aligned holes in the hinge plates,strut web ends 49 and the pivot 'block 17 so as hingedly to fasten thestrut S and the hinge plates to the pivot block. Suitable retainers 34are received on the projecting ends of the pin 27, held as by transversepins. Washers 50 are desirably interposed between the retainers 34 andthe surfaces of the hinge plates 18 so that the hinge plates can turnfreely on the pins in the up and down swinging movement of the boom.

At its forward or right-hand end (Fig, l), the strut assembly S issuspended from load bar (Fig. 4) of a trolley comprising two pairs ofwheels 24 and yokes 23 that supportingly receive oppositely directedhorizontal end portions 51 of the load bar 20. Forward web portions 52of the strut channel member 19 are disposed one ou each side of and inembracing relation to a depending bifurcated end 53 of the T-shaped loadbar 20. A transverse pin 2S is received through aligned holes in thestrut channel webs 52, the bifurcated load bar body 53 and a sheave 21that is located in the space between the depending leg portions of thelatter. Suitable pin-held retainers 33 on the projecting ends of themain pin 28 hold the latter in place, and a suitable ball or otherantifriction assembly 54 is used in the mounting of the sheave 21 on thecenter of the pin 2S so that the sheave turns freely during the payingout and drawing in movements of the boom hoist cable 25, as will appear.

The boom trolley wheel pairs 24 ride along the lower ilanges 56 of anarcuately curved track member 35 secured tothe underside of the rolledsteel L-sectioned members 10 comprising one of the trucks of thecarrier. The track 35 may comprise a rolled steel I-beam providing topflanges 57 which are bolted or otherwise secured to and against theunderside of the truck members 10, and track flanges 56 that carry thetrolley wheels 24. The curvature of the track 35 corresponds to that ofan arc of a circle having its center on the axis of the pin 40 of thepivot block 17 so that the trolley wheels 24 ride smoothly along thetrack flanges 56 during rotative or side to side horizontally swingingmovement of the strut assembly S and the boom B as an integrated unitand as between the broken and full line positions of Fig. 2. At the endsof the track stop blocks 58 are secured as by bolts 59 against theundersides of the flanges 56 to engage the boom trolley and limit theturning movement of the boom and strut assembly about its vertical axis.

The boom B is of box construction, being fabricated from rolled steelmembers and plates. I-n the arrangement shown, top and bottom channels60 and 61 are disposed in confronting relation to one another and aresecured together by a series of side plates 62 riveted to the anges ofthe channel members. The base or lefthand end of the boom (as viewed inFig. l) is received between the depending portions of the hinge plates18 to which the members of the boom are secured as by riveting andwelding. At its forward or right-hand end (as viewed in the same gure)the boom is tted with a conventional hook 32 Ifor carrying a load 64 asby means of a sling 65. Desirably the boom is tapered, having itsmaximum section at a lifting point spaced from the base end of the booma distance corresponding to the length of the strut member S, so that inthe raised position of the boom, shown by the full lines of Fig. 1, asheave 22 carried by a pin 66 held at the lift point of the boom isdirectly below and in the plane of the sheave 21 carried by the load bar20. A cable 25 running from electric hoist 26 fast on the strut channels19 adjacent the pivot block 17 at the base end of the strut assembly istrained over the sheave 21, thence downwardly and under the boom sheave22 and thence upwardly to the strut S, the end of the hoist cable beingfast to the strut adjacent the sheave 21. In addition to having itsmaximum section at or adjacent the lift pointV of the sheave pin 66, theboom is `formed with a bend at such section so that in raised positionthe forward portion of the boom between the lift point and t-he hook 32extends upwardly at an acute angle to the horizontal, the hook beingthus movable to a point above the level of the base of the boom andabove the strut S. Although a hook 32 of elementary type is shown, it isapparent that the end of the boom may be equipped with any of variousload handling devices such as a grab, forks, or turning and stackingimplements. In the event such load handling devices require poweroperation, it is feasible to rig them with riving components extendingthrough the hollow interior of the boom, a suitable drive motor oractuator being located on a rearward extension 68 of the boom in lieu ofcounterbalance or weight 13.

in the proportioning of the dilerent parts of the boom, regard must behad to the weight and character of load that is to be handled. Since theload 64 applies a downward force on the outer end of the boom, thereaction of the load pin 66 on the hoist cable 25 is likewise downwardlyand the pin 27 at the base end of the boom reacts upwardly against thepivot block 17. Thus the boom constitutes a third degree lever and theload carrying capacity of the boom is limited by the strength of theboom in resisting bending moments, by the tensile strength of the hoistcable 25, and by the strength of the carrier C and bridge A componentson the right of the crane structure (as viewed in Figs. l and 2). Theupward reaction against the pivot block 17 resulting from a load on theboom hook 32 tends to raise the carrier trolley wheels 6 at the leftside of the carrier (as viewed in Figs. l and 2) off the track 8. Underextremely heavy loads it is apparent that an upward reaction mightresult-against the left side of the bridge (as viewed in Figs. l and 2),tending also to raise the bridge trolley wheels 3 off the runway railsl.

As a stabilizer for the boom, to counterbalance the weight of theprojecting outer portion of the boom and any load carried by the hook32, the weight 13 is mounted at the base end of the boom, this weightcomprising a concrete or metal block or, as previously mentioned, a

drive motor for a mechanical grab or other device utilized in lieu ofthehook 32. To further counterbalance the boom and any load carriedthereby, a weight 12 is mounted on the left side of the carrier (asviewed in Fig. 1). This weight also may comprise a biock of metal orconcrete or a sutable drive and controls for shifting the carrier C backand forth across the bridge rails 8. ln addition to or in lieu of theweights 12 and 13, or one of them, the carrier suspension mayincorporate rollers (not shown) mounted as on the load carrying elements37 to engage against and ride along the underside or sides of the bottomflanges of the left-hand track 8, such rollers serving to preventraising of the trolley wheels 6 otf the track flanges. Other rollers(not shown) can be incorporated in the trolley structure of the bridge Ato prevent raising of the rollers 3 off the track lianges of the runwayrails 1.

The length of the forward portion of the boom B between the liftpin 66and the load hook 32 is determined by the permissible reactions on theload pins of the strut-boom assembly, upward on the pin 27 and downwardon the pin 28. The longer the forward portion of a boom, the greater thereactions against these pins for a given load. In the arrangement shownthe distance between the load pin 66 and the hook 32 is approximatelytwice the distance between such pin and the pivot pin 27 so that, inaccordance with well known principles, the load that can be accommodatedon the hook is one-third the lifting capacity of the hoist 26. Thus ahoist capable of exerting a 3,000-pound lifting force on the pin 66 iscapable of lifting a load 64 of approximately 1,000 pounds suspendedfrom the hook 32, less the dead load of the beam. A `geometricalarrangement proportioned and arranged as shown is suitable for use inmany material handling situations, particularly in the placement ofcrated items and the like into the covered body of a van or trailer 70,indicated in phantom in Fig. l.

In the operation of the boom-crane as in loading the van 7i) the boom 29swings up and down as between the broken and full lines shown in Fig. 1,this movement being in a vertical plane normal to the axis of thehorizontal pivot pin 27 and being common to both the boom and the strutassembly 19. When the boom is lowered to the broken line position shownthe sheave 22 is displaced horizontally and the forces in the fixed andmovable runs of the hoist cable 25 include horizontal components thatreact against the pin 28 in the load bar 2t) of the boom trolley. Thepresence of the strut member S, however, and its connection to andbetween the main pivot pin 27 and the forward trolley pin 28 relieve theboom trolley and the carrier structure of the horizontal forcecomponents resulting from the boom load. Since the strut member S andthe boom B are received at their base ends on a common horizontal pin 27and at the forward end of the strut assembly the boom is suspended fromthe pin 28 by the hoist cable, the strut and boom are constrained tohorizontal movement in unison. Thus at all times they are disposed in acommon vertical plane. Such side to side movement of the boom and strutwith the boom trolley wheels 24 traveling along the arcuate track 35 iseffected manually or through cable and pulleys actuated by suitableelectric drive means (not shown). Such a drive may be carried by eitherthe strut assembly or the carrier frame members 11 and conventionallycontrolled.

Lateral stability is imparted to the boom B through the rigidly attachedhinge plates 18 that embrace the pivot block 17, the latter in turnbeing rotatable on its vertical axis and held against turning on ahorizontal axis by the iiatwise engagement of the top of the blockagainst the underside of the bottom flange 41 of the support beam 14.The pivot or hinge block 17 is drawn and held snugly against the bottomiiange of the beam by the nut 15 acting against the thrust bearingassembly 8 16. Thus the pivot or hinge block 17 and associatedcomponents, while permitting up and down swinging of the boom in avertical plane and side to side rotative turning as a unit of thestrut-boom combination about a vertical axis through the pin 40,prevents lateral twisting of both the strut and the boom.

In Figs. 6-11 is illustrated a modification of the invention in whichparts corresponding to those described in connection with the precedingfigures are indicated by the same refcrence numerals and similar orcorresponding parts are indicated by the same numerals primed. in thismodication a boom 29 is capable of continuous or 360 rotative movementabout its vertical axis,instead of the limited arcuate side to sideswinging movement of the corresponding boom 29 previously described. Thetruck frame members 2 of the crane bridge A overhang or extend beyondboth of the bridge cap members in cantilever fashion and at their endsare supported on trolley assemblies corresponding to the double trolleyWheel pairs described in connection with the suspension of the forwardor right-hand side of the bridge crane of Figs. 1 and 2. The carrierstructure C', comprising a rectangular frame having the truck members1t) and cross members i1, as previously described, is suspended by thetrolley wheels 6 from the bridge rails 8.

ln the full swiveling modification of Figs. 6-11 the boom-strut unit issuspended wholly by fore and aft trolleys that ride on the lower flangesof a circular track 72. This track is formed of a rolled steel I-beambent into circular form and its ends joined as by welding to form acomplete annulus having the desired diameter, here shown as beinggreater than the distance between the rails 8 of the bridge A. Thecircular track 72 is secured to the underside of the carrier as bybolting its upper anges to and against the undersides of the carriermembers 1) and 11. Certain of the carrier truck members, indicated at10', are extended beyond the cross frame members l1 so as to provideadditional support for the circular track to which they are connectedthrough spacers (not shown).

The strut S of the embodiment of Figs. 6-11 is of modified constructionand comprises a pair of rolled steel channels 73 and 74 disposed inspaced parallel relation, with the openings in the channels facingoutwardly. The forward or right-hand end of the strut is suspened by apair of double wheel trolleys and related parts as described inconnection with the embodiment of Figs. 1 and 2. Instead of being pinnedto the extreme end of the strut as in the arrangement of Figs. 1 and 2,the bifurcated end 53 of the load bar 20 is received and held by the pin28 between the strut channels 73 and 74 at a point spaced from theforward end of the strut to provide an overhang cantilever end on thelatter, which carries a latching mechanism for locking the boom inraised position, as will later appear.

The rear or left-hand end of the strut S is suspended from the track 72by a trolley assembly shown in Fig. 10. The trolley wheels 76, in pairs,turn on aligned stub shafts fast in the upper ends of the arms of yokes77. A load bar 78 formed with a depressed or underslung central portionand raised ends is carried between the yokes, the raised ends of theload bar being received within the yokes and located and held in placeon suitable bearing elements. The load bar is formed with one or morelateral flanges 79 along the bottom edge or edges of its underslungcentral portion, these flanges being bolted as at 80 to the upperflanges of the channels 73 and 74 comprising the strut S.

A pivot or hinge block 17 corresponding to the block 17 previouslydescribed is disposed between the spaced hinge plates 18 of the boom andcarries the hinge pin 27 which constitutes one of the points ofconnection between the boom and the carrier and on which the boom issuspended and swings in a vertical plane. The block 17' is connectedrigidly to the rear or base end of the strut S.

either directly or, as shown, by means of an interposed bracket 85fabricated from a short piece of rolled steel I-beam section and plates.Bolts and screws 81 and 82 or other suitable fasteners secure the number85 to and against the bottom of the strut S and to and against the topof the pivot block 17 respectively. By reason of the rigid connectionthus established between the pivot block 17 and the strut S' the boom Bis constrained to swinging movement in the plane of the strut S.

Rollers 86 are recessed in wells 87 formed in the load bar 78 and turnon pins or spindles 89 held at their ends in the load bar. These rollersare disposed to engage against underside 90 of the bottom flange of thecircular track 72 to transmit to the track any upward force applied bythe base of the boom through the pivot pin 27 resulting say, from heavyor excessive loading of the hook or grab 32. Similar rollers may beprovided in the load carrying elements 37 or elsewhere on the carrier totransmit any upward forces from the carrier C to the bottoms of thetracks 8 of the crane bridge A.

As an optional feature of construction and as one of the advantages andobjectives of the invention, means is provided for guiding or centeringthe rotation of the strutboom combination on the carrier C' to relievethe trolleys associated with the wheels 24 and 75 of horizontal loads. Acentral frame member 91 is supported on and secured to the cross framemembers 11 of the carrier, this frame member being midway between andparallel to the truck members The ends of the central frame member,which member may comprise a rolled steel I-beam, project cantileverfashion beyond the cross frame members 11 and are fastened todiametrically opposite points of the circular track 72 throughinterposed spacers. Thus the central frame member provides support forthe circular track in addition to that obtained through the truck frameand cross frame members of the carrier. At its center or mid-point,which is also the center of the carrier, the frame member 91 has securedagainst its underside as by bolts 92 a bracket 93 on the bottom of whichis mounted a tough wear resistant metal pivot block 94. A central recess95 in this block receives for free turning movement an upstanding pin 96carried on a plate 97 welded or otherwise secured to channel shapedspacers 98 that are fast to the top ilanges of the strut channels 73 and74. A plate 99 is interposed and secured between the strut members andthe spacers 98, and another reinforcement plate 100 is welded to thebottom of the ystrut members. Rotation of the strut-boom unit relativeto the carrier is centered on the axis of the pin 96. Horizontal forcesbetween the boom and the carrier are thus transf mitted through the pin96, thereby relieving the circular track 72 and the trolley wheelsassociated therewith from such loads.

On the cantilevered forward end of the strut S is carried a latchelement 102 that is arranged to eifect interlocking connection with amating latch element 103 secured to the boom B for the purpose ofholding and supporting the forward or load carrying end of the boom inraised position, as shown in Fig. 6. The latch element 102 is a toughsteel forging or casting having a rectangular base secured to the angesof the strut members 73 and 74 as by bolts 104. Depending or projectingdownwardly from the base of the latch element is an integral bifurcatedstructure comprising arms 106 and 107 defining between them a latchsocket or recess 108. The latch element 103 also comprises a tough metalforging or casting having a rectangular base secured as by bolts 109 tothe top of the boom B. An integral leg or prong 110 projects upwardlyfrom the base of the element 103, the parts of the two latch elementsbeing so oriented that when the boom is raised the prong 110 moves intothe latch recess 108 of the latch element on the strut in position to beheld by a retractable pin 111 guided in a bore 112 formed in a lateralboss extension 114 of the arm 107. A helical coil spring 115 is receivedabout a reduced diameter stem portion 116 of the pin 111 and within therecess 112. The spring reacts against the shoulder of the pin and thecircular wall at the inner end of the bore 112, biasing the pin to theleft (as viewed in Fig.` 8) for movement across the latch recess 108 andinto an aligned socket 117 in the latch arm 106 so that in its projectedposition shown the pin 111 is supported at both ends by the arms 106 and107.

When the boom B is in the raised position shown in Figs. 6 and 8 and thepin 111 is projected across the latch recess 108 it is received throughan opening 118 in the prong to effect an interlock between the elementsor components of the latch mechanism and thereby hold the boom in raisedposition. The central portion of the pin 111 may be formed with adepressed saddle 119 providing axially spaced shoulders engageable.against opposite sides of the prong 110 to prevent endwise shifting ofthe pin when loaded by the weight of the boom.

The end of the reduced diameter stern 116 projects through an axialguide hole in the end of the boss extension 114 and carries a transversepin 120 the ends of which are received in parallel slots 121 in thespaced portions of a bifurcated arm 122 of a bell crank lever. Thislever is carried on a pin 123 supported between the strut channelmembers 73 and 74. A pull cord 125 is connected to the other ann 124 ofthe bell crank lever for actuating the latch mechanism to retract thepin 111 into the bore 112 and thereby release the prong 110 so that theboom is free to move up and down -as actuated by the hoist. When it isdesired to release the latch from the locked position shown, the hoist26 is first energized sufliciently to relieve the pin 111 of load sothat it may be readily withdrawn by actuation of the bell crank leverthrough the cord 125.

Latching the boom to the strut in the manner described relieves thehoist cable 25 of load and permits the electric drive motor of the hoist26 to be de-energized. Thus the latch arrangement constitutes a safetymeasure which prevents -inadvertent lowering of the boom.

Figs. 6-11 illustrate a further variation and combination of parts thathas advantages in situations requiring occasional lifting of loadsheavier than can be accommodated conveniently on the hook or grab 32.This arrangement uses, in lieu of the lixed sheave 22 described inconnection with Figs. l and 2, a separable block 126 that carries asheave 127 about which the hoist cable 25 is reeved. The block 126 i-sformed with or carries across its sides and ends a load receivingelement or elements 128 which may collectively take the form of anannulus that closely embraces the casing of the block, being eitherintegral therewith or rigidly secured thereto as 'by welding. In thenormal operation of the crane-boom loader cornbination the block 126 isdisposed within the box structure of the boom at the lift point which isalso the intersection of the base portion and the forwardly extendingload carrying portion that are angularly disposed relative to eachother. A pair of bearing members 130 and 131 are arranged inside theboom, being suitably secured to the insides of the top and bottom boomchannel members 60 and 61 and the side plates 62. The members 130 and131 may comprise steel castings or forgings and define between them aguideway 132 that accommodates the block 126. Supplemental plates 138secured against the sides of the boom at the lift point reinforce theangle joint between the base and forward boom portions. The upperportion of the guideway, indicated at 133, is of reduced section in theprovision of one or more shoulders 134 engageable with the load elements128 on the block 126 so as to locate the block in the guideway in boomlifting position and prevent movement of the block upwardly through theguideway portion 133 of reduced section. An opening 135 is formed in thetop boom channel member 60 -in alignment with the guideway portion 133to accommodate theupper end ofthe block and the vertical runs dicated bythe broken lines of Fig. 6. When the block is thus released from theboom it can be used in the usual manner for directly lifting and movingloads, a suitable hook or grab 146 being fast on the block for suchpurpose.

The present invention thus provides a crane hoist-boom loadercombination in which a lever type boom is sus-iv pended wholly below thecarrier of an overhead crane in the provision of a unique low overheadload handling apparatus that can be readily maneuvered for shifting,lifting and placing loads in narrow, low overhead locations that wouldotherwise be inaccessible with conventional cranes and loaders. Numerouscombinations and arrangements of the structures described are feasibleat the option of the builder of the crane. Provision is made for eitherlimited horizontal swinging of the boom as in the arrangement of Figs. land 2 or for complete 360 swiveling if such is desired, as in thearrangement of Figs. 6 and 9.

In accordance with the patent statutes the principles of the presentinvention may be utilized in various ways, numerous modifications andValterations being contemplated, substitution of parts and changes inconstruction being resorted to as desired, it being understood that theembodiments shown in the drawings and described above are given merelyfor purposes of explanation and illustration without intending to limitthe scope of the claims to the spechic details disclosed.

What I claim and desire to secure by Letters Patent of the United Statesis:

l. A low overhead traveling crane comprising a carriage adapted totravel along a rail and a cantilever boom disposed below and suspendedfrom the carriage, the boom suspension comprising a ull circle trackbelow the carriage, trolley trucks mounted on the track in diametricpositions, ymeans connecting the trolley trucks for movement about thetrack in unison, a horizontal pivot pin connecting one point of the boomto one of the trucks for swinging movement solely about a horizontalaxis, and a hoist connecting another point of the boom to another of thetrucks.

2. In an overhead crane of the type comprising rail means supported in agenerally horizontal plane above an area to be serviced by the craneanda carriage mounted on the rail means for movement in said plane, thecornbination of a carrier, means securing the carrier to the carriagefor relative rotative movement about a vertical axis, an elongated rigidcantilever boom, means suspending the boom from the carrier, the boomsuspension means including pivot means connected between the carrier andone end of the boom and hoist means connected between points of thecarrier and the boom spaced horizontally from the pivot means and fromthe other end of the boom and constituting the latter a third degreelever, latch means comprising separable interlockingelements, one on thecarrier, the other on the boom, each spaced from the pivotal axis of theboom and engageable with one another to hold the boom against swinging;and thereby locked in fixed relation to the carrier, the hoist includinga block, separable connection means between the block and the 'boom atsaid point of the latter intermediate its ends, the

eparable connection means between the block and the boom comprisingelements having complemental shoulders engageable with one another toconnect the block operatively to the boom for raising the latter and Cltpermitting the block to drop by gravity away from the Y boom when thelatter is latched to the carrier for use of the block in direct litthoisting operations independently of the booml` the complementalshoulders of the connecting elements effecting automatic reconnection ofthe block to the boom upon raising of the block to a predeterminedposition relative to the boom for immediate use of the block inactuating the boom in hoisting operations.

3. An overhead crane comprising in combination a pair of runway railsadapted to be supported in spaced parallel relation above an area to beserviced by the crane, a main bridge structure adapted to be mounted onand to travel horizontally along said pair of runway rails, a carriagestructure adapted to be mounted on the main bridge structure forhorizontal movement therealong in a direction generally transverse tothe horizontal travel direction of the main bridge structure on therunway rails, a carrier comprising a rigid horizontal strut, meanssuspending the carrier from the carriage structure, the carriersuspension means including means providing rotative movement of thecarrier relative to the carriage structure about a vertical axis, anelongated rigid cantilever boom, means suspending the boom from thecarrier, the boom suspension means including pivot lmeans connectedbetween the carrier and one end of the boom and hoist means connectedbetween points of the carrier and the boom spaced horizontally from thepivot means and from the other end of the boom and constituting thelatter a third degree lever, the pivot means constraining the boom toswinging movement solely in a vertical plane relative to the horizontalstrut of the carrier, latch means comprising separable interlockingelements, one on the carrier, the other on the boom, each spaced `fromthe pivotal axis of the boom and engageable with one another to hold theboom against swinging and thereby locked yin xed relation to thecarrier, the hoist including a block, separable connection means betweenthe block and the boom at said point of the latter intermediate itsends, the separable connection means between the block and the boomcomprising elements having complemental shoulders engageable with oneanother to connect the block operatively to the boom for raising thelatter and permitting the block to drop by gravity away from the boomwhen the latter is latched to the carrier for use of the block in directlift hoisting operations independently of the boom, the complementalshoulders of the connecting elements effecting automatic reconnection ofthe block to the boom upon raising of the block to a predeterminedposition relative to the boom for immediate use of the block inactuating the boom in hoisting operations.

4. In an overhead crane of the type comprising rail means adapted to besupported in a generally horizontal plane above an area to be servicedby the crane and a carriage frame mounted on the rail means for movementin said plane, the combination of a carrier, means suspending thecarrier from the carriage, an elongated cantilever boom having an innerpivot end and an outer load lcarrying end, a pin joint connecting theinner end of the boom to the carrier and constraining the movement ofthe boom relative to the carrier to swinging in a vertical plane, ahoist connected between points of the carrier and the boom spacedhorizontally from the pin joint to raise and lower the boom relative tothe carrier, the boom point to which the hoist is connected beingintermediate and spaced from both ends of the boom, latch meanscomprising separable interlocking elements, one on the carrier, theother on the boom, each spaced from the pivotal axis of the boom andengageable with one another to hold the boom against swinging andthereby locked in fixed relation to the carrier, the hoist including ablock and flexible cable means running from the carrier to the block,separable connection means between the block and the boom comprisingelements having complemental shoulders engageable with one another toconnect the-block operatively to the boom for raising the llatter andpermitting the block to drop away from the boom by gravity when thelatter is latched to the carrier for use of the block in direct lifthoisting operations independently of the boom, the complementalshoulders of the connecting elements effecting automatic reconnection ofthe block to the boom upon raising of the block References Cited in thele of this patent to a predetermined position relative to the boom form- UNITED STATES PATENTS mediate use of the block in actuating the boom-in boom 666 123 Wellman et al Jan 15 1901 hoisting operations, one ofthe connection elements being 734187 Matthews July 21 1903 an outerelement carried by the boom and having a ver- 5 854837 Paige May 28,1907 tical through opening receiving the cable means, and the 1,334,892Dickinson Man 23, 1920 other of the connection elements being on theblock, the 1,794,714 Kiphnger Mar. 3, 1931 one element constituting aguide for the cable means in 1,799,209 Bennington Apr. 7, 1931 directlift hoisting operations and in raising the block to lo 1,818,374Bennington Aug. 11, 1931 said boom hoisting position. 2,553,378 MillerMay 15, 1951

